In known embodiments, the closing of sliding doors is monitored by means of sensors which can detect an object in the path of movement of a door leaf, that is to say that the sensor ascertains whether or not an object is present. A further differentiation does not take place.
Accordingly, when an object is detected, the sliding door is always opened completely. In winter, however, the problem arises of keeping a sliding door closed, if possible, in order to avoid heat losses from rooms that can be entered via the sliding door.
One known solution for losing less heat in such situations consists in not opening the door completely. Since persons expect the door to open completely, a collision between persons and the door that has not been completely opened regularly occurs.